Pre-Tensioned Discrete Element Support System

ABSTRACT

A matting system comprised of an assembly of discrete, individual small mat segments connected by pre-tensioned cable elements. The mat segments are configured to displace at the connecting surfaces of the mat segments at a predetermined load. The pre-tensioned cable elements holding the mat segments together are elastic through a reasonable displacement range so that the mat segments of the matting system will reassemble after the applied load is removed.

PRIORITY

This application claims priority to U.S. provisional application Ser.No. 61/655,017 tiled Jun. 4, 2012, the entire content of which is herebyincorporated by reference.

FIELD OF THE INVENTION

This invention relates generally to the field of construction and cranematting, and more particularly to a pre-tensioned matting assemblycomprised of a plurality of is discrete mat segments.

BACKGROUND OF THE INVENTION

Matting systems are utilized to provide temporary support surfaces orstructures for construction sites and for temporary roadways. Suchmatting systems are typically utilized in areas having poor soilconditions that would not otherwise be accessible to heavy trucks,cranes, and construction equipment. Typical matting systems arecomprised of a plurality of boards or panel elements that are fastenedtogether to create a mat surface. Such designs rely on the properties ofthe beam strength (strength is in direction of beam) of the boards orpanel elements that are fastened together to form a matting system.

The failure of such matting systems is primarily is due to excessivemoment loads on the mat components (mat bending). Increasing the size ofthe boards or panel elements of the matting system increases the momentload potential for the matting system. Thus, a very small mat isdifficult to break when compared to a large mat. In practice, mats thatare very small are not practical to use because of high installationcosts and the number of connections required.

Consequently, a need exists for a matting system that will have the loadbearing characteristics of a very small mat with the constructionefficiency associated with large matting systems.

SUMMARY OF THE INVENTION

The presented design provides a matting system having a supportstructure configured for a desired maximum design load for placement ona comparatively compliant underlayment or sub-base (soil in the case ofa construction mat). When design load (rated load) for the mattingsystem is exceeded, the support structure undergoes a geometrical changein configuration that allows additional support for the applied loadfrom the underlying elements.

The presented design provides a matting system comprised of an assemblyof a plurality of discrete, individual small parts or mat segments thatare held together by a pre-tensioned wire or rod connector. The matsegments are designed to “give”, i.e. separate, at their adjoiningconnecting surfaces when the matting system is overloaded. Thepre-tensioned connector holding the mat segments together is elasticthrough a reasonable displacement range so that the matting system willreassemble itself after the applied load is removed. Energy stored inthe pre-tensioned connector assembly facilitates the positive return ofthe overstressed support structure back to its initial configuration.

In the presented design, the primary strength (for the matting systemhaving a one dimensional tension system) is in the direction ofassembly. The prefabricated “beam” of mat segments may be relativelyweak when initially fitted together but the beam strength of the matsegments greatly enhanced when the mat segments are linked together bythe pre-tensioned connector. Further, the construction geometry of thelinked mat segments need not be limited to the shape of a beam or anyother particular shapes. The mat segments would be made from a varietyof skeletonized elements framed by a matrix of suitable material such asone made from plastic composites.

The construction described above can stand on its own or could be partof a more complicated composite structure that satisfies additionalfunctional needs. As an example, an assembly of rigid structuralelements could be covered by a softer outer material. This outermaterial could act to protect the rigid structural elements from impactloads and could also serve the activity for which the mat is employed(e.g., non-skid surface). In this way, multiple support structures couldbe housed in matting system comprised, of a matrix of differingmaterial.

The matting system may also be provided with pre-tensioned connectors inmultiple dimensions.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-section view of a matting system in accordance withthe description set forth herein.

FIG. 2 is a partial top view of the matting system shown in FIG. 1

FIG. 3 is a schematic cross-section view of the matting system of FIG. 1showing the interaction of the mat segment elements in response to anapplied load that is less than the system design load.

FIG. 4 is a cross-section view of the matting system of FIG. 1 showingthe interaction of the mat segment elements in response to an appliedload, that is greater than the system design load.

FIG. 5 is a cross-section view of a matting system in accordance withthe description set forth herein, the matting system being placed overan uneven support surface.

FIG. 6 is an alternate embodiment of the matting system of FIG. 1.

FIG. 7 is an alternate embodiment of the matting system of FIG. 1 havinga shear force resistant mat segment interface.

FIG. 8 is an alternate embodiment of the mat segments of the mattingsystem of FIG. 1, showing a mat segment having a skeletonized frameconfigured for a matrix filling of a desired material.

FIG. 9 shows an internal support frame or rib element for a mat segment.

FIG. 10 is a cross-sectional view of an alternate embodiment of the matsegments of the matting system of FIG. 1, showing a mat segment havingthe internal ribs shown in FIG. 9.

FIG. 11 is schematic top view of an alternate embodiment of the matsegments of the matting system of FIG. 1 with the connectors configuredto intersect at a desired direction.

DESCRIPTION OF THE EMBODIMENT

Referring now to FIG. 1 and FIG. 2, there is shown the matting system(10) of Applicant's invention. The matting system (10) is comprised of aplurality of discrete, individual mat segments (12), preferably instrips or splines, each having at least one retainer bore (15). The matsegments (12) are held together by a pre-tensioned wire or rod connector(14) positioned through the retainer bore (15) of the adjoining matsegments and secured in tension by a fastener such as a nut (16).Placing the connector (14) in tension in the manner similar to that usedin post-tensioned concrete slabs is thought to be suitable. The wire orrod connector (14) may be of any suitable material thought it is thoughtthat steel rods or steel wire cables will be utilized.

The mat segments (12) are designed to “give” or separate at theiradjoining connecting surfaces (11) at a predetermined load as thepre-tensioned connector rod deforms when the matting system isoverloaded. As shown multiple mat segments are utilized to create thematting system (10). These mat segments (12) have an adjoiningconnecting surface (11) that is designed to facilitate deflection of themat segments 12) during periods when the matting system is overloaded.It is thought that a matting system (to) comprised of mat segments (12)having connecting surfaces (11) comprised of concave surfaces (18)interfacing with adjoining convex surfaces (20) will serve to providethe desired deflection of the mat segments.

The pre-tensioned connector (14) holding the mat segments (12) togetheris designed to be elastic through a desired range of load conditions anddisplacements of adjoining mat segments (12) so that the matting system(10) will reassemble itself after the applied load is removed. Energystored in the pre-tensioned connector (14) in the elastic range of thepre-tensioned connector will facilitate the positive return of thedisplaced mat segments (12) back to the initial mat configuration whenthe load displacing the mat segments and overstressing the mattingsystem (to) is removed.

As further shown in FIG. 1 and FIG. 2, the interconnected mat segments(12) of the matting system (10) may include a surfacing overlay (21) toprovide a non-skid surface to enhance surface traction, to protect thecomponents of the mat segments from impact loads to prevent wear andtear, or to enhance weather resistance. The surfacing overlay (21) maybe a discontinuous us overlay shown as (22) which would cover eachindividual mat segment (12) or a continuous overlay shown as (24) thatwould cover the upper surface of multiple mat segments (12) or thesurface of the entire matting system (10). The overlay (21) may alsocover the entire matting system (10), top and bottom, or the mattingsystem (10) may be completely encased or encapsulated by the overlay(21).

Placement of the desired surfacing overlay (21) may be varied over theupper surface of the matting system (10) so that the overlay (21) may betailored as desired to provide a surfacing (21) specific to a desireduse. The surfacing overlay (21) may be any suitable surfacing materialsuch as resilient asphalt or other pliable surfacing material such as areplaceable composite or wooden surfacing. Resilient asphalt may beparticularly suitable for a mat system (10) having a continuous overlay(24).

FIG. 3 shows a schematic cross-section view of the matting system (10)of FIG. 1 positioned on an under-laying surface (30) to depict theinteraction between adjoining mat segments (12) in response to anapplied load (P) that is less than the design load of the mattingsystem. A desired tension load (T) is applied by the pre-tensionedconnector (14) Which compresses the mat segments (12) together. In sucha position the mat segments (12) are held together by the tensionedconnector (14) with the concave surfaces (20) positioned within theconvex surfaces (18) of adjoining mat segments 12).

FIG. 4 shows a schematic cross-section view of the matting system (10)of FIG. 1 positioned on an under-laying surface (30) to depict theinteraction between adjoining mat segments (12) in response to anapplied load (P) greater than the design load of the matting system. Asshown the pre-tensioned connector (14) is held at a desired designtension load (T) which compresses the mat segments (12) together. Theconnector (14) holds the mat segments (12) together and provides apredetermined reasonable elastic range of displacement of adjoining matsegments (12). This elastic range allows the adjoining mat segments (12)to be temporarily displaced from each other under overload as shown,with the concave surfaces (20) moved from within the convex surfaces(18) of adjoining mat segments (12). The mat segments (12) return to theconfiguration shown in FIG. 3 when the applied load (P) is decreased tothe design load or less or removed, all together. When the design load(P) (rated load) for the matting system (10) is exceeded, the mattingsystem (10) undergoes a geometrical change in configuration of the matsegments (12) that allows additional support for the applied load fromthe underlying subgrade elements.

FIG. 5 shows a cross-section schematic view of a matting system (10) inaccordance with the description set forth herein, The matting system(10) is shown being placed over an uneven subgrade support surface (30).For installation over varying, uneven, or imperfect subgrade (30), suchas one have a curb (32) or a surface depression, mat segments (12) thematting system (10) may be placed as desired to conform to and cover anysurface curb (32) or surface depression. Then matting system (10) maybepost-tensioned by applying tension forces to the connector (14) torestrain the mat segments together to enhance the structural integrityof the matting system. Because the mat segments (12) are held togetherby a desired tension (T) in the connector (14) at a predeterminedelastic range, the matting system (10) provides for displacement of thesegments so that it may be used over uneven support surfaces (30).

Release of tension from the connector (14) will allow the mat to bereformed for another use in another configuration increasing theversatility and applications for the matting system.

Other configurations may also be utilized for the connection surfaces ofadjoining mat segments (12) of a matting, system (10), For example, thematting system (10) may be configured simply as an enlarged two or threesegment matt with adjoining segments (12) having a single concavesurface adjoining a single convex surface as the connecting surface (11)as shown in FIG. 6. The matting system (10) could be comprised of matsegments (12) having adjoining connecting surfaces (11) for resistingshear forces. One such configuration may be adjoining mat segments (12)having a shear key or tongue (11 a) and a keyway or groove (11 b) forthe connecting surfaces (11) as shown in FIG. 7.

A schematic top view of another embodiment of a mat segment (12) isshown in FIG. 8. Referring to FIG. 8, the matting system (10) may becomprised of a plurality of mat segments (12) having an externalskeleton or frame (13) comprised of external frame walls (13 a). Thewalls (13 a) provide an open area (17) for containing a filling of asuitable matrix material (17 a), such as a polymer matrix. The walls (13a) of the skeletonized frame (13) of the mat segments (12) may be madeof any suitable material such as aluminum, aluminum alloys, steel, orplastic or polymer composites. The matrix (17 a) may be a polymercompound, an asphalt mix, concrete, or another suitable fill material.Desired adjoining connecting surfaces (11) may be incorporated into theframe (13) such as surfaces for facilitating deflection or for resistingshear loads.

Each mat segment (12) could also be provided with an internal supportframe or rib element (19) such as that shown in FIG. 9. The rib element(19) may include a retainer bore (15) for receiving a connector (14). Apolymer matrix molded around the internal frame (19) would complete amat segment (12). The rib element (19) may be fabricated as a metalcasting or from a molded polymer. As shown, the rib element (19) may beprovided with the mat connecting surfaces (11) comprised of concavesurfaces (18) interfacing with adjoining convex surfaces (20) or anyother suitable connecting surfaces. FIG. 10 presents a schematic sideview of an alternate embodiment of the mat segments (12) of the mattingsystem of FIG. 1, showing a mat segment having the internal ribs (19)with concave surfaces (18) interfacing with adjoining convex surfaces(20) as shown in FIG. 9.

The construction described above for the matting system (10) can standalone as a single mat or could be incorporated into a more complicatedmatting structure that satisfies additional functional needs. Thematting system (10) may be configured with mat segments (12) havingpre-tensioned or post-tensioned connectors (14) extending in multipledirections through the mat segments (12) as desired to provideadditional mat flexibility and to distribute bending loads on thematting system (10) in multiple directions. For example, as shown inFIG. 11, connectors (14) may be configured to intersect or cross each ata desired angle such as diagonally or at ninety degree angles to retainthe mat segments (12) in a matting system (10) in a desired position.

It will be evident that various other changes may be made in the form,construction and arrangement of the parts of the matting systemdescribed herein without departing from the spirit and scope of theinvention or sacrificing its material advantages. It is thought that theproposed matting system presented herein will be understood from theforegoing description. The form described herein is intended to bemerely an example embodiment of the invention.

I claim:
 1. A matting system comprising: (a) a plurality of discrete matsegments, each said mat segment configured with corresponding adjoiningconnecting surfaces, whereby when said adjoining connecting surfaces arefitted together, said adjoining connecting surfaces facilitatedisplacement of said mat segments at a predetermined mat load; (b) anelongated connector extending through each said mat segment, saidconnector being placed in tension to hold said mat segments together ina desired configuration.
 2. The matting system recited in claim 1wherein said elongated connector is elastic through a desireddisplacement range.
 3. The matting system as recited in claim 2 whereinenergy stored said connector facilitates the return of displaced matsegments to their initial configuration upon removal of saidpredetermined mat load.
 4. The matting system as recited in claim 3wherein said mat segments are comprised of: (a) an outer frame,comprised of a plurality of frame segments, said frame segments hayingsaid corresponding adjoining connecting surfaces; and (b) a matrixretained within said outer frame.
 5. The matting system as recited inclaim 4 wherein said matrix fill retained within said outer frame is apolymer composite.
 6. The matting system as recited in claim 3 whereinsaid corresponding adjoining connecting surfaces comprise concavesurfaces interfacing with adjoining convex surfaces.
 7. The mattingsystem as recited in claim 3 wherein said corresponding adjoiningconnecting surfaces have shear resistant surfaces.
 8. The matting systemas recited in claim 3 wherein said mat segments are comprised of apolymer composite.
 9. The matting system as recited in claim 3 whereinsaid elongated connector is pre tensioned.
 10. The mating system asrecited in claim 3 wherein said elongated connector is post-tensioned.11. The matting system as recited in claim 8 wherein said polymercomposite segments have an internal rib structure.
 12. The mattingsystem as recited in claim 11 wherein said internal rib structure ofpolymer composite mat segments have said corresponding adjoiningconnecting surfaces.
 13. The matting system as recited in claim 3wherein said mat segments are provided with a plurality of elongatedconnectors, said elongated connectors intersecting at a desired angle.14. A matting system comprising: (a) a plurality of discrete matsegments, each said mat segment configured with corresponding adjoiningconnecting surfaces, whereby when said adjoining connecting surfaces arefitted together, said adjoining connecting surfaces facilitatedisplacement of said mat segments through a range of predetermined matloads; (b) an elongated connector extending through each said matsegment, said connector being placed in tension to hold said matsegments together in a desired configuration, said elongated connectorbeing elastic through said range of predetermined mat loads to allowdisplacement of said discrete mat segments with respect to each other;and (c) wherein said connector facilitates the return of said matsegments to their initial configuration after displacement upon removalof said predetermined mat loads.
 15. The matting system as recited inclaim 14 wherein said corresponding adjoining connecting surfacescomprise concave surfaces interfacing with adjoining convex surfaces.16. The matting system as recited in claim 15 wherein said mat segmentsare comprised of; (a) a frame comprised, of a plurality of frame membersforming a framed opening, said frame members having correspondingadjoining connecting surfaces; and (b) a fill material retained in saidframed opening.
 17. The matting system as recited in claim 14 whereinsaid polymer composite mat. segments have an internal rib structure. 18.The matting system as recited in claim 17 wherein said mat segments arecomprised of a polymer composite.
 19. The matting system as recited inclaim 14 wherein said elongated connector is pre-tensioned.
 20. Thematting system as recited in claim 14 wherein said elongated connectoris post-tensioned.
 21. matting system as recited in claim 14 whereinsaid mat segments are covered by an overlay material.